Introduce suspenders:factories generator (#1136)

Maintains functionally with the [existing generator][] while adding
support for the [default Rails test suite]. With this change, the
generator can be invoked on a Rails application that uses RSpec or the
[default Rails test suite][].

Adds generator which adds a test to lint all Factories in an effort to
improve developer experience.

Additionally, we remove the generation of the `dev:prime` task as we
felt that should be the responsibly of another generator.

[existing generator]: https://github.com/thoughtbot/suspenders/blob/main/lib/suspenders/generators/factories_generator.rb
[default Rails test suite]: https://guides.rubyonrails.org/testing.html

NEWS.md

@@ -4,6 +4,7 @@ Unreleased
 * Introduce `suspenders:accessibility` generator
 * Introduce `Suspenders::Generators::APIAppUnsupported` module and concern
 * Introduce `suspenders:inline_svg` generator
+* Introduce `suspenders:factories` generator
 
 20230113.0 (January, 13, 2023)
 

README.md

@@ -30,6 +30,27 @@ Installs [capybara_accessibility_audit] and [capybara_accessible_selectors]
   [capybara_accessibility_audit]: https://github.com/thoughtbot/capybara_accessibility_audit
   [capybara_accessible_selectors]: https://github.com/citizensadvice/capybara_accessible_selectors
 
+### Factories
+
+Build test data with clarity and ease.
+
+This uses [FactoryBot] to help you define dummy and test data for your
+test suite. The `create`, `build`, and `build_stubbed` class methods are
+directly available to all tests.
+
+We recommend putting FactoryBot definitions in one `spec/factories.rb`
+(or `test/factories`) file, at least until it grows unwieldy. This helps reduce
+confusion around circular dependencies and makes it easy to jump between
+definitions.
+
+Supports the [default test suite] and [RSpec].
+
+`bin/rails g suspenders:factories`
+
+  [Factory Bot]: https://github.com/thoughtbot/factory_bot_rails
+  [default test suite]: https://guides.rubyonrails.org/testing.html
+  [RSpec]: https://rspec.info
+
 ### Inline SVG
 
 Render SVG images inline using the [inline_svg] gem, as a potential performance

lib/generators/suspenders/factories_generator.rb

@@ -0,0 +1,66 @@
+module Suspenders
+  module Generators
+    class FactoriesGenerator < Rails::Generators::Base
+      include Suspenders::Generators::Helpers
+
+      source_root File.expand_path("../../templates/factories", __FILE__)
+      desc <<~TEXT
+        Build test data with clarity and ease.
+
+        This uses FactoryBot to help you define dummy and test data for your test
+        suite. The `create`, `build`, and `build_stubbed` class methods are directly
+        available to all tests.
+
+        We recommend putting FactoryBot definitions in one `spec/factories.rb` (or
+        `test/factories`) file, at least until it grows unwieldy. This helps reduce
+        confusion around circular dependencies and makes it easy to jump between
+        definitions.
+
+        Supports the default test suite and RSpec.
+      TEXT
+
+      def add_factory_bot
+        gem_group :development, :test do
+          gem "factory_bot_rails"
+        end
+
+        Bundler.with_unbundled_env { run "bundle install" }
+      end
+
+      def set_up_factory_bot
+        if default_test_helper_present?
+          insert_into_file Rails.root.join("test/test_helper.rb"), after: "class TestCase" do
+            "\n    include FactoryBot::Syntax::Methods"
+          end
+        elsif rspec_test_helper_present?
+          copy_file "factory_bot_rspec.rb", "spec/support/factory_bot.rb"
+          insert_into_file Rails.root.join("spec/rails_helper.rb") do
+            %(Dir[Rails.root.join("spec/support/**/*.rb")].sort.each { |file| require file })
+          end
+        end
+      end
+
+      def generate_empty_factories_file
+        if default_test_suite?
+          copy_file "factories.rb", "test/factories.rb"
+        elsif rspec_test_suite?
+          copy_file "factories.rb", "spec/factories.rb"
+        end
+      end
+
+      def remove_fixture_definitions
+        if default_test_helper_present?
+          comment_lines "test/test_helper.rb", /fixtures :all/
+        end
+      end
+
+      def create_linting_test
+        if default_test_suite?
+          copy_file "factories_test.rb", "test/factory_bots/factories_test.rb"
+        elsif rspec_test_suite?
+          copy_file "factories_spec.rb", "spec/factory_bots/factories_spec.rb"
+        end
+      end
+    end
+  end
+end

lib/generators/templates/factories/factories.rb

@@ -0,0 +1,2 @@
+FactoryBot.define do
+end

lib/generators/templates/factories/factories_spec.rb

@@ -0,0 +1,7 @@
+require "rails_helper"
+
+RSpec.describe "Factories" do
+  it "has valid factoties" do
+    FactoryBot.lint traits: true
+  end
+end

lib/generators/templates/factories/factories_test.rb

@@ -0,0 +1,9 @@
+require "test_helper"
+
+class FactoryBotsTest < ActiveSupport::TestCase
+  class FactoryLintingTest < FactoryBotsTest
+    test "linting of factories" do
+      FactoryBot.lint traits: true
+    end
+  end
+end

lib/generators/templates/factories/factory_bot_rspec.rb

@@ -0,0 +1,5 @@
+FactoryBot.use_parent_strategy = true
+
+RSpec.configure do |config|
+  config.include FactoryBot::Syntax::Methods
+end

lib/suspenders/generators.rb

@@ -2,6 +2,24 @@
 
 module Suspenders
   module Generators
+    module Helpers
+      def default_test_suite?
+        File.exist? Rails.root.join("test")
+      end
+
+      def rspec_test_suite?
+        File.exist? Rails.root.join("spec/spec_helper.rb")
+      end
+
+      def default_test_helper_present?
+        File.exist? Rails.root.join("test/test_helper.rb")
+      end
+
+      def rspec_test_helper_present?
+        File.exist? Rails.root.join("spec/rails_helper.rb")
+      end
+    end
+
     module APIAppUnsupported
       class Error < StandardError
         def message

test/generators/suspenders/factories_generator_test.rb

@@ -0,0 +1,225 @@
+require "test_helper"
+require "generators/suspenders/factories_generator"
+
+module Suspenders
+  module Generators
+    class FactoriesGenerator::DefaultTest < Rails::Generators::TestCase
+      include Suspenders::TestHelpers
+
+      tests Suspenders::Generators::FactoriesGenerator
+      destination Rails.root
+      setup :prepare_destination
+      teardown :restore_destination
+
+      test "generator has a description" do
+        description = <<~TEXT
+          Build test data with clarity and ease.
+
+          This uses FactoryBot to help you define dummy and test data for your test
+          suite. The `create`, `build`, and `build_stubbed` class methods are directly
+          available to all tests.
+
+          We recommend putting FactoryBot definitions in one `spec/factories.rb` (or
+          `test/factories`) file, at least until it grows unwieldy. This helps reduce
+          confusion around circular dependencies and makes it easy to jump between
+          definitions.
+
+          Supports the default test suite and RSpec.
+        TEXT
+
+        assert_equal description, FactoriesGenerator.desc
+      end
+
+      test "installs gem with Bundler" do
+        Bundler.stubs(:with_unbundled_env).yields
+        generator.expects(:run).with("bundle install").once
+
+        capture(:stdout) do
+          generator.add_factory_bot
+        end
+      end
+
+      test "removes fixture definitions" do
+        File.open(app_root("test/test_helper.rb"), "w") { _1.write test_helper }
+
+        run_generator
+
+        assert_file app_root("test/test_helper.rb") do |file|
+          assert_match(/# fixtures :all/, file)
+        end
+      end
+
+      test "adds gem to Gemfile" do
+        run_generator
+
+        assert_file app_root("Gemfile") do |file|
+          assert_match(/group :development, :test do\n  gem "factory_bot_rails"\nend/, file)
+        end
+      end
+
+      test "includes syntax methods" do
+        File.open(app_root("test/test_helper.rb"), "w") { _1.write test_helper }
+
+        run_generator
+
+        assert_file app_root("test/test_helper.rb") do |file|
+          assert_match(/class TestCase\n    include FactoryBot::Syntax::Methods/, file)
+        end
+      end
+
+      test "creates definition file" do
+        definition_file = <<~RUBY
+          FactoryBot.define do
+          end
+        RUBY
+
+        run_generator
+
+        assert_file app_root("test/factories.rb") do |file|
+          assert_match definition_file, file
+        end
+      end
+
+      test "creates linting test" do
+        factories_test = <<~RUBY
+          require "test_helper"
+
+          class FactoryBotsTest < ActiveSupport::TestCase
+            class FactoryLintingTest < FactoryBotsTest
+              test "linting of factories" do
+                FactoryBot.lint traits: true
+              end
+            end
+          end
+        RUBY
+
+        run_generator
+
+        assert_file app_root("test/factory_bots/factories_test.rb") do |file|
+          assert_match factories_test, file
+        end
+      end
+
+      private
+
+      def prepare_destination
+        mkdir "test"
+        touch "Gemfile"
+      end
+
+      def restore_destination
+        remove_dir_if_exists "test"
+        remove_file_if_exists "Gemfile"
+        remove_dir_if_exists "lib/tasks"
+      end
+
+      def test_helper
+        <<~RUBY
+          ENV["RAILS_ENV"] ||= "test"
+          require_relative "../config/environment"
+          require "rails/test_help"
+
+          module ActiveSupport
+            class TestCase
+              # Run tests in parallel with specified workers
+              parallelize(workers: :number_of_processors)
+
+              # Setup all fixtures in test/fixtures/*.yml for all tests in alphabetical order.
+              fixtures :all
+
+              # Add more helper methods to be used by all tests here...
+            end
+          end
+        RUBY
+      end
+    end
+
+    class FactoriesGenerator::RSpecTest < Rails::Generators::TestCase
+      include Suspenders::TestHelpers
+
+      tests Suspenders::Generators::FactoriesGenerator
+      destination Rails.root
+      setup :prepare_destination
+      teardown :restore_destination
+
+      test "includes syntax methods" do
+        touch("spec/rails_helper.rb")
+        factory_bot_config = <<~RUBY
+          FactoryBot.use_parent_strategy = true
+
+          RSpec.configure do |config|
+            config.include FactoryBot::Syntax::Methods
+          end
+        RUBY
+
+        run_generator
+
+        assert_file app_root("spec/support/factory_bot.rb") do |file|
+          assert_match factory_bot_config, file
+        end
+        assert_file app_root("spec/rails_helper.rb") do |file|
+          assert_match(/Dir\[Rails\.root\.join\("spec\/support\/\*\*\/\*\.rb"\)\]\.sort\.each { \|file\| require file }/, file)
+        end
+      end
+
+      test "creates definition file" do
+        definition_file = <<~RUBY
+          FactoryBot.define do
+          end
+        RUBY
+
+        run_generator
+
+        assert_file app_root("spec/factories.rb") do |file|
+          assert_match definition_file, file
+        end
+      end
+
+      test "does not modify rails_helper if it's configured to include support files" do
+        touch("spec/rails_helper.rb")
+        rails_helper = <<~RUBY
+          Dir[Rails.root.join("spec/support/**/*.rb")].sort.each { |file| require file }
+        RUBY
+        File.open(app_root("spec/rails_helper.rb"), "w") { _1.write rails_helper }
+
+        run_generator
+
+        assert_file app_root("spec/rails_helper.rb") do |file|
+          assert_equal rails_helper, file
+        end
+      end
+
+      test "creates linting test" do
+        factories_spec = <<~RUBY
+          require "rails_helper"
+
+          RSpec.describe "Factories" do
+            it "has valid factoties" do
+              FactoryBot.lint traits: true
+            end
+          end
+        RUBY
+
+        run_generator
+
+        assert_file app_root("spec/factory_bots/factories_spec.rb") do |file|
+          assert_match factories_spec, file
+        end
+      end
+
+      private
+
+      def prepare_destination
+        mkdir "spec"
+        touch "spec/spec_helper.rb"
+        touch "Gemfile"
+      end
+
+      def restore_destination
+        remove_dir_if_exists "spec"
+        remove_file_if_exists "Gemfile"
+        remove_dir_if_exists "lib/tasks"
+      end
+    end
+  end
+end